Possible causes

– OD Pressure Switch harness is open or shorted
– OD Pressure Switch circuit poor electrical connection
– Faulty OD Pressure Switch
– Internal transmission damage
– Faulty Engine Control Module (ECM)
– Faulty Transmission Control Module (TCM)

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)
– Transmission will not shift gears.

P0871 CHRYSLER Description

The Transmission Control Module (TCM) has detected a fault in the pressure switch assembly